1. dominant disorders
   1. locus
      1. chormosomal location of a specific gene
      2. heterogeneity
         1. mutation at different loci = same phenotype
         2. ex: Polycystic kidney disease
            1. PKD2 chr 4
            2. PKD1 chr 16
   2. allele
      1. different forms, or DNA sequences, that a gene may have in a population
      2. heterogeniety
         1. different mutatin at same locus = same condition
         2. ex: cystic fibrosis
            1. CFTR
   3. clinical heterogeneity
      1. different clinical disease (phenotype) caused by different mutation in same gene
      2. ex: COL1 mutation
         1. Ehlers danlos
         2. OI
2. definitions
   1. genotype
      1. alleles at a given locus
         1. * genetic constitution
   2. phenotype
      1. physically observable
         1. results from
            1. interaction of genotype & environment
            2. clinical manifestation of genotype*
   3. genocopy
      1. genotype that determines
         1. a phenotype closely similar to
            1. that determined by
            2. a different genotype
   4. phenocopy
      1. environmental mimics of
         1. genetic conditions
3. medelian or single gene disorder
   1. a trait or medical disorder which follows a pattern of inheritance
      1. x-linked recessive
      2. x-linked dominant
      3. autosomal dominant
      4. autosomal recessive